1. Technical Field
The disclosure generally relates to power supply circuits, and especially to a power supply circuit for protecting electronic devices from being damaged when an AC power supply is over voltage or under voltage.
2. Description of Related Art
In alternating current (AC, also ac), the movement of electric charge regularly reverses direction. AC is the form in which electric power is delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal. A certain electronic devices nowadays do not have the ability to receive an AC voltage. Take 115V and 220VAC voltages as an example, the 115V and 220V AC voltages are variable from 100V to 240V. An over voltage or under voltage may be input in the electronic devices and can damage these electronic devices.
Therefore there is a need for improvement in the art.